The present invention relates to devices and systems for modulating the temperature of a working surface. More specifically, this invention relates to a device and a system for modulating the temperature of a working surface while exposing the working surface to radiation.
Lasers are known to have numerous medical applications. For example, lasers are used to ablate and cauterize tissue. Lasers are also used in a variety of therapeutic dermal procedures including removal of unwanted hair and treatment of Port Wine Stains or cutaneous vascular lesions. Some of the earliest attempts to develop therapeutic dermal procedures using lasers are described by Solomon and Goldman in xe2x80x9cHistopathology of Laser Treatment of Port Wine Lesions: Biopsy Studies of Treated Area up to Three Years After Laser Impactsxe2x80x9d, published in The Journal of Investigative Dermatology 50, 141, 1968.
During the early stages of developing these therapeutic dermal procedures there was speculation regarding the transient modification of the skin prior to treatment with the laser source. Gilchrest et al. teach cooling the epidermis prior to treatment of Port Wine Stains with an argon laser in xe2x80x9cChilling Port Wine Stains Improves Response to Argon Laser Therapyxe2x80x9d published in Plastic and Reconstructive Surgery 69, 2, 1982. Gilchrest et al. states that Port Wine Stains are more violaceous (pinkish red) when cooled and thus exhibit improved absorption of the laser radiation. In xe2x80x9cArgon Laser Therapy of Port-Wine Stains: Effects and Limitationsxe2x80x9d published in Plastic and Reconstructive Surgery, 75 (4) 1985, Yanai et al. reported one of the first attempts to treat dermis with a laser source while simultaneously cooling. Yanai et al. used an admixture of cold water and ice circulated through an apparatus formed from two acrylic plates. The apparatus was placed on the target tissue and the laser therapy was conducted through the apparatus. The results of Yanai et al. were not statistically convincing of the benefits of cooling dermis during exposure to a laser source. Never-the-less further studies have been convincing regarding the benefits of cooling dermis during laser treatment and today cooling dermis while exposing the dermis to a laser source is a preferred method for both hair removal, vascular lesions and malformations and the treatment of Port Wine Stains.
A cooling apparatus and method for removing hair is described in U.S. Pat. Nos. 5,735,844 and 5,595,568, both issued to Anderson et al. A cooling apparatus and method for targeting cutaneous vascular lesions is described in U.S. Pat. Nos. 5,057,104 and 5,282,797, both issued to Chess. The cooling devices described within these patents have a propensity to develop or collect condensation on the optical window of the cooling device during laser treatment. The condensation or xe2x80x9cfoggingxe2x80x9d not only obstructs the physician""s view of the tissue, but also scatters the laser light leading to incomplete or inconsistent treatment of the target dermis. Because of the fogging, some physicians apply a wax or ointment to the optical window of the cooling device to reduce the condensation. However, waxes and ointments wear off or streak the optical window and again reduce the physician""s visibility of the target tissue and increase laser scatter.
The apparatus of the current invention is configured for modulating the temperature of a working surface while simultaneously exposing the working surface with a radiation source. The apparatus has lens sections which form an optical window that is transparent to the radiation being used. The lens sections are formed from any suitable transparent material, but preferably include at least one formed from sapphire. The apparatus of the instant invention preferably is configured for regulating the temperature of a target tissue while the target tissue is simultaneously being exposed to a laser source. The apparatus, also referred to herein as an applicator, is preferably used in procedures to remove hair or to treat cutaneous vascular lesions or other dermal malformations.
The applicator has a first lens section and a second lens section. The first lens section has an outer lens and an inner lens. The outer lens and the inner lens are preferably spaced apart by an average distance of 0.1 to 1.0 cm to form an insulating region between the outer lens and the inner lens. The second lens section is preferably positioned coincident to the first lens section such that the first lens section and the second lens section form the optical window. The optical surface area of the first and the second lens sections are preferably matched or, alternatively, are different. Further, the lens sections are flat or shaped to focus or modulate the radiation being used. Preferably, the optical surface area of the second lens section is in a range of 1.0 to 50 cm2 and has a shape that is suitable for use in medical laser procedures, such as curved or flat.
The first and the second lens sections form the boundaries of a medium cavity configured to channel a temperature modulating medium. The first and the second lens sections are preferably secured together by a frame section which secures the first and the second lens sections in a position, whereby the first and the second lens sections are separated by an average distance between 0.05 to 0.5 cm. The frame section has a first and a second aperture through which the temperature modulating medium enters and exits the medium cavity. At least one of the first and second apertures is preferably fenestrated to control the flow of the temperature modulating medium through the medium cavity. The first aperture is coupled to an inlet section and the second aperture is coupled to an outlet section each configured to be coupled to a corresponding outlet and inlet of a circulating mechanism. The circulating mechanism urges the temperature regulating medium through the medium cavity and preferably controls the temperature of the medium.
According to a preferred embodiment of the invention the insulating region is under vacuum. Accordingly, the outer lens and the inner lens of the first lens section form a thermo-pane structure. Alternatively, the insulating region may contain an insulating gas, such as dry nitrogen or air. Alternatively, the insulating region is configured with a second inlet and a second outlet, wherein a second temperature modulating medium is channeled through the insulating region.
The applicator is a hand-held applicator configured to be controlled independently from a laser source, wherein a handle section secures to the frame section at a preferred angle relative to the optical window. Alternatively, the handle section is hingably coupled to the frame section, such that the optical window can assume a range of angles relative to the handle section. In further embodiments, the inlet and outlet sections are integral with the handle section and pass through the handle section to couple to the circulating mechanism.
In the system of the instant invention, the applicator is coupled to a laser source or optics for delivering the radiation from the laser source to the target tissue. Accordingly, the system includes a bracket section for coupling the applicator to a laser housing structure. Preferably, the bracket secures the applicator in a position which allows the laser to pass directly through the optical window of the applicator. The applicator is coupled to the laser housing by any number of bracket designs, but is preferably coupled through the inlet and outlet sections, whereby the bracket attaches to the inlet and outlet sections.
In an alternate system of the instant invention, the system has an optical configuration for delivering radiation from a radiation source to a target tissue. The optical configuration includes an applicator coupled to a radiation source or suitable optics for delivering the radiation to the target tissue. Suitable optics include, but are not limited to, focusing lens, mirrors and optical fibers. Preferably, the radiation source is a laser source with a wavelength in the range of 400 to 11,000 nm. More preferably, the laser source is a pulsed laser source configured to generate a predetermined pulsed sequence during procedures for removing hair or for treating cutaneous vascular lesions.
In use the epidermis of the target tissue is exposed to the predetermined sequence of laser pulses through the transparent window of the applicator. A temperature modulating medium is channeled through the medium cavity and through the inlet and outlet sections. In the preferred method of the instant invention, the medium is cooled and removes heat from the target tissue.
As mentioned, the bottom lens section is flat or contoured depending on the desired focusing properties of the window and/or the morphology of the target tissue being treated. The outer surface of the bottom lens section is placed in contact with the epidermis of the target tissue during the laser exposure. Alternatively, a dye, a gel, an oil or other suitable contact medium is placed between the epidermis and the outer surface of the second lens section to facilitate the transfer of radiation to the tissue, the transfer of heat to the applicator and/or to reduce friction between the applicator and tissue when pressure is applied.
The temperature modulating medium is preferably a cooled liquid medium, such as a mixture of approximately 50% water and 50% ethylene glycol. The cooled liquid medium is circulated through the medium cavity by a circulation mechanism with a pump unit and a refrigerator unit. The refrigerator unit preferably cools the liquid medium to temperatures between xe2x88x9210 to +10 degrees centigrade before recirculating the liquid medium through the medium cavity of the applicator.
During treatment of the target tissue, the insulating region helps to modulate or regulate the temperature of the outer surface of the first lens section. Accordingly, while cooling the target tissue, the insulating region helps to prevent the transfer of heat from the outer lens of the first lens section to the cooling medium and, thereby, reduces fogging on the outer surface of the first lens section.
The insulating region is preferably a vacuum insulating region or a dry gas. Alternatively, the insulating region is configured with an inlet and an outlet to channel a second temperature modulating medium, whereby the second temperature modulating medium modulates the temperature of the outer lens of the first lens section.